Java Reference
In-Depth Information
operators, and method invocations. An assignment statement instructs the computer to
evaluate (that is, to compute the value of) the expression on the right-hand side of the
equal sign and to set the value of the variable on the left-hand side equal to the value of
that expression. The following are examples of Java assignment statements:
totalWeight = oneWeight * numberOfBeans;
temperature = 98.6;
count = count + 2;
The first assignment statement sets the value of
totalWeight
equal to the number in
the variable
oneWeight
multiplied by the number in
numberOfBeans
. (Multiplication
is expressed using the asterisk
*
in Java.) The second assignment statement sets the
value of
temperature
to
98.6
. The third assignment statement increases the value of
the variable
count
by
2
.
Note that a variable may occur on both sides of the assignment operator (both sides
of the equal sign). The assigned statement
count = count + 2;
sets the new value of
count
equal to the old value of
count
plus
2
.
When used with variables of a class type, the assignment operator requires a bit
more explanation, which we will give in Chapter 4 .
Assignment Statements with Primitive Types
An assignment statement with a variable of a primitive type on the left-hand side of
the equal sign causes the following actions: First, the expression on the right-hand side of
the equal sign is evaluated, and then the variable on the left-hand side of the equal sign is
set equal to this value.
SYNTAX
Variable = Expression;
EXAMPLE
distance = rate * time;
count = count + 2;
An assigned statement may be used as an expression that evaluates to a value. When
used this way, the variable on the left-hand side of the equal sign is changed as we
have described, and the new value of the variable is also the value of the assignment
expression. For example,
number = 3;
